Hitachi SAMURAI Series Service Manual page 162

4. Troubleshooting
Analysis and countermeasure of abnormalities
Phenomenon
Faulty PCB
Pump is
operating,
but fan and
Failure of remote control switch
compressor
are not
Faulty elec-
operating.
tromagnetic
switch of fan
(in cooling)
Pump ·
Faulty elec-
Compressor
tromagnetic
is operating,
switch of fan
but fan is not
(in heating)
operating.
Faulty PCB
Faulty elec-
tromagnetic
Pump · Fan is
contactor of
operating, but
compressor
compressor is
not operating
Activation of
high pressure
switch due to
excessively
high
Chiller Unit
discharge
stops during
pressure
Cooling
operation
Thermostat
for discharge
gas overheat
prevention is
activated
154
SMGB0082 rev.1 - 07/2015
Cause
Bad connection of wiring
Faulty PCB
Disconnection of coil
Bad connection of contact
Faulty Fan Motor
Disconnection of coil
Bad connection of contact
Faulty fan module
Bad connection of wiring
Faulty PCB
Defective thermistor
Disconnection of coil
Bad connection of contact
Thermostat is operating
Faulty compressor motor
Faulty compressor
Low voltage at startup.
Insufficient airflow to air-side
heat exchanger.
High temperature of the air
passing through the air-side
heat exchanger
Refrigerant overcharge
Mixture of non-condensable
gas in refrigerant cycle
Clogging of discharge pipes
Clogging of expansion valve
Clogging of check valve (air-
side heat exchanger side)
Clogging of strainer
High temperature of the cold
(hot) water inlet at the water-
side heat exchanger
Suction gas temperature is
too high.
(Excessive super heat)
Check Item
Check connection with a tester
Check connection with a tester
Check PCB with self-diagnosis
Operation is possible by activation
from the main unit side
Check connection with a tester
Voltage measurement between
contacts of electromagnetic switch
Measure resistance between wires
Check connection with a tester
Voltage measurement between
contacts of electromagnetic switch
Inspection of fan module
Check connection with a tester
Measure resistance of thermistor
Check connection with a tester
Voltage measurement between
contacts of electromagnetic
contactor
Try to turn the knob of the
thermostat, in order to change the
temperature.
Measure resistance between wires
Howling sounds originating from
compressor
Voltage measurement
Excessive adherence of dust at the
air-side heat exchanger
Air-side heat exchanger inlet or
outlet blocked
Insufficient service space for the
chiller unit
Inverse rotation of the fan motor
Chiller unit is air short-circuited
Other heat source near the chiller
unit
Check cycle temperature
Stop the chiller unit and check the
relation between water temperature
and pressure
Check for clogging
Check difference of temperature
before and after the strainer
Check whether the usage range is
being exceeded
Gas leakage or insufficient
refrigerant
Wrong activation of the 4-way valve
or internal leakage
Malfunction of the expansion valve
Action · Countermeasure
Correct wiring connection
Replace PCB
Replace remote control
switch
Replace electromagnetic
switch
Replace fan motor
Replace electromagnetic
contactor
Replace fan module
Correct wiring connection
Replace thermistor
Replace electromagnetic
contactor
This is not a failure.
Compressor replacement
Consult with the power
company
Remove.
Secure service space
Change wiring of fan
motor
Remove short-circuit
Remove heat source
Charge correct volume
Recharge refrigerant
after vacuum pumping
Check for clogging
Remove clogging, or
replace check valve
Replace or wash the
strainer
Investigate the situation
of heat load well and
take action
Charge correct
refrigerant volume after
checking gas leakage
Replace 4-way valve
Replace expansion valve